title: Tetra-phenyl-phospho-nium iodide-1,3,5-tri-fluoro-2,4,6-tri-iodo-benzene-methanol (3/4/1).
abstract: The crystallization of a 1:1 molar solution of 1,3,5-tri-fluoro-2,4,6-di-iodo-benzene (TFTIB) and tetra-phenyl-phosponium iodide (TPPI) from methanol produced tetra-gonal needles of pure TPPI and tabular pseudo-hexa-gonal truncated bipyramids of the title compound, 3C24H20P(+)·3I(-)·4C6F3I3·CH4O or (TPPI)3(TFTIB)4·MeOH. The asymmetric unit is composed of six TPPI mol-ecules, eight TFTIB mol-ecules and two methanol mol-ecules, overall 16 constituents. The formation of the architecture is essentially guided by a number of C-I⋯I(-) halogen bonds (XB), whose lengths are in the range 3.276 (1)-3.625 (1) Å. Layers of supra-molecular polyanions are formed parallel to (10-1) wherein iodide anions function as penta-, tetra- or bidentate XB acceptors. The structure is not far from being P21/n, but the centrosymmetry is lost due to a different conformation of a single couple of cations and the small asymmetry in the formed supra-molecular anion. One methanol mol-ecule is hydrogen bonded to an iodide anion, while the second is linked to the first one via an O-H⋯O contact. This second methanol mol-ecule is more loosely pinned in its position than the first and presents very high anisotropic displacement parameters and a seeming shortening of the C-O bond length. The crystal studied was refined as a perfect inversion twin.
authors.affiliation: NFMLab, Department of Chemistry, Materials and Chemical Engineering, "Giulio Natta", Politecnico di Milano, Via Mancinelli, 7, I-20131 Milano, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Cavallo
authors.forename: Pierangelo
authors.initials: P
authors.lastname: Metrangolo
authors.forename: Tullio
authors.initials: T
authors.lastname: Pilati
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Resnati
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Terraneo